The U.S. Food and Drug Administration approved AstraZeneca PLC and Merck & Co. Inc.'s Lynparza as maintenance therapy for women with certain types of ovarian, fallopian tube and peritoneal cancer.

Lynparza, or olaparib, is the first in a class of medicines known as PARP inhibitors to garner U.S. regulatory approval as first-line maintenance therapy for advanced ovarian cancer featuring a mutation in the BRCA gene. PARP inhibitors work by trapping the PARP enzyme on sites of DNA damage. This action prevents the DNA in cancer cells from being repaired and causes the cancer cells to die.

The approval is based on the results of a phase 3 trial, called SOLO-1, which showed that Lynparza cuts the risk of ovarian cancer returning by 70% when given to newly diagnosed women whose tumors shrank or disappeared after initial treatment with chemotherapy.

The drug has been previously approved by the FDA to treat patients with BRCA-mutated breast cancer and certain ovarian cancer mutations.

The FDA has granted Lynparza an orphan drug designation for the treatment of pancreatic cancer. Results from a late-stage study evaluating Lynparza's effectiveness in that disease are expected in the first half of 2019.

Lynparza is also being developed for prostate cancer. A trial found that the drug in a combination with a standard of care hormone therapy performed better than the hormone therapy alone to delay the progression of prostate cancer.

The U.S. FDA also approved BRACAnalysis CDx, a diagnostic test which determines if ovarian cancer patients are eligible to receive Lynparza.